1. Field of the Invention
The present invention relates to a laser scanning device and a method using the same.
2. Description of Related Art
Skill persons have paid much attention on laser etching technique capable of replacing a conventional chemical wet etching technique with high-pollution.
U.S. Pat. No. 6,574,024 discloses a homogenization method of a laser beam on an optical mask through a scan beam to implement laser micro-drilling. According to such patent, a homogenization module first homogenises energy of the laser beam, and then the homogenised laser beam is used to perform the micro-drilling operations through a scanning mirror. However, the laser micro-drilling technique cannot be applied for a large area stitching, and a photolithography process of a non-circular spot cannot be used.
Moreover, U.S. Pat. No. 4,699,515 discloses a method for detecting and calibrating a relative error between a photomask and a wafer during a semiconductor fabrication process. In this patent, the error calibration is performed according to a single movement or rotation, and the relative error is calibrated according to relative movement or rotation between the photomask and a carrier platform. The disclosed technique has an advantage of high stitching accuracy, though a processing speed thereof is slow, and such technique is not suitable of a scanner processing system.
A processing speed of the laser in cooperation with the photomask technique is generally unsatisfactory. Therefore, a new technique combining the photomask technique and the scanning mirror is provided. During a development process of the new technique, it is discovered that the non-circular spots of different scan areas may have a rotation phenomenon, which may lead to failure of the large area stitching. The rotation is generated due to a skew error or an angular error, etc. between the scanning mirrors, and such error belongs to a production error generated during the assembling.
Taking a scanning system of a single scanning mirror as an example, during an x-axis projection processing, a processing path is represented by an x(θx) function, though an error parameter θy is input to the function (θy, is defined as an angle error generated during an x-axis scanning) due to the assembling problem, and the angle error can cause the problem of spot rotation.
Regarding the problem of spot rotation, since it is difficult and complicated to gradually modify the scanning mirror system, an effective solving method is required to be developed.